Synthesis, spectroscopy and spectroelectrochemistry of chlorocarbonyl {1,2-bis[(2,6-diisopropylphenyl)imino]-acenaphthene-kappa(2)-N,N '}rhodium (I)

Reaction of the dinuclear complex [{Rh(CO)(2)}(2) (mu-Cl)(2)]with an alpha-diimine ligand, 1,2- bis[(2,6-diisopropylphenyl) imino] acenaphthene (iPr(2)Ph-bian), produces square-planar [RhCl(CO)(iPr(2)Ph-bian)]. For the first time, 2: 1 and 1: 1 alpha-diimine/dimer reactions yielded the same product. The rigidity of iPr(2)Ph-bian together with its flexible electronic properties and steric requirements of the 2,6-diisopropyl substituents on the benzene rings allow rapid closure of a chelate bond and replacement of a CO ligand instead of chloride. A resonance Raman study of [RhCl(CO)(iPr(2)Ph-bian)] has revealed a predominant Rh-to-bian charge transfer (MLCT) character of electronic transitions in the visible spectral region. The stabilisation of [RhCl(CO)(iPr(2)Ph-bian)] in lower oxidation states by the pi-acceptor iPr(2)Ph-bian ligand was investigated in situ by UV-VIS, IR and EPR spectroelectrochemistry at variable temperatures. The construction of the novel UV-VIS-NIR-IR low-temperature OTTLE cell used in these studies is described in the last part of the paper.

Ambient water quality criteria for acenaphthene /

Mode of access: Internet.

Hidrocarbonetos policíclicos aromáticos (HPAS) em cachaça, rum, uísque e álcool combustível

The concentration of 15 polycyclic aromatic hydrocarbons (PAHs) in 57 samples of distillates (cachaça, rum, whiskey, and alcohol fuel) has been determined by HPLC-Fluorescence detection. The quantitative analytical profile of PAHs treated by Partial Least Square - Discriminant Analysis (PLS-DA) provided a good classification of the studied spirits based on their PAHs content. Additionally, the classification of the sugar cane derivatives according to the harvest practice was obtained treating the analytical data by Linear Discriminant Analysis (LDA), using naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benz[b]fluoranthene, and benz[g,h,i]perylene, as a chemical descriptors.

Polycyclic aromatic hydrocarbon levels in three pelagic fish species from Atlantic Ocean: inter-specific and inter-season comparisons and assessment of potential public health risks

The concentrations of 18 polycyclic aromatic hydrocarbons (PAHs) were determined in three commercially valuable fish species (sardine, Sardina pilchardus; chub mackerel, Scomber japonicus; and horse mackerel, Trachurus trachurus) from the Atlantic Ocean. Specimens were collected seasonally during 2007–2009. Only low molecular weight PAHs were detected, namely, naphthalene, acenaphthene, fluorene and phenanthrene. Chub mackerel (1.80–19.90 microg/kg ww) revealed to be significantly more contaminated than horse mackerel (2.73–10.0 microg/kg ww) and sardine (2.29–14.18 microg/kg ww). Inter-specific and inter-season comparisons of PAHs bioaccumulation were statistically assessed. The more relevant statistical correlations were observed between PAH amounts and total fat content (significant positive relationships, p < 0.05), and season (sardine displayed higher amounts in autumn–winter while the mackerel species showed globally the inverse behavior). The health risks by consumption of these species were assessed and shown to present no threat to public health concerning PAH intakes.

Analysis of polycyclic aromatic hydrocarbons in fish: evaluation of a quick, easy, cheap, effective, rugged, and safe extraction method

QuEChERS method was evaluated for extraction of 16 PAHs from fish samples. For a selective measurement of the compounds, extracts were analysed by LC with fluorescence detection. The overall analytical procedure was validated by systematic recovery experiments at three levels and by using the standard reference material SRM 2977 (mussel tissue). The targeted contaminants, except naphthalene and acenaphthene, were successfully extracted from SRM 2977 with recoveries ranging from 63.5–110.0% with variation coefficients not exceeding 8%. The optimum QuEChERS conditions were the following: 5 g of homogenised fish sample, 10 mL of ACN, agitation performed by vortex during 3 min. Quantification limits ranging from 0.12– 1.90 ng/g wet weight (0.30–4.70 µg/L) were obtained. The optimized methodology was applied to assess the safety concerning PAHs contents of horse mackerel (Trachurus trachurus), chub mackerel (Scomber japonicus), sardine (Sardina pilchardus) and farmed seabass (Dicentrarchus labrax). Although benzo(a)pyrene, the marker used for evaluating the carcinogenic risk of PAHs in food, was not detected in the analysed samples (89 individuals corresponding to 27 homogenized samples), the overall mean concentration ranged from 2.52 l 1.20 ng/g in horse mackerel to 14.6 ± 2.8 ng/ g in farmed seabass. Significant differences were found between the mean PAHs concentrations of the four groups.

Synthesis, characterization and reactivity of new cobalt, palladium and nickel complexes bearing α-diimines and P, O ligands

This work describes the synthesis and characterization of a series of new α-diimine and P,O, β-keto and acetamide phosphines ligands, and their complexation to Ni(II), Co(II),Co(III) and Pd(II) to obtain a series of new compounds aiming to study their structural characteristics and to test their catalytic activity. All the compounds synthesized were characterized by the usual spectroscopic and spectrometric techniques: Elemental Analysis, MALDI-TOF-MS spectrometry, IR, UV-vis, 1H, 13C and 31P NMR spectroscopies. Some of the paramagnetic compounds were also characterized by EPR. For the majority of the compounds it was possible to solve their solid state structure by single crystal X-ray diffraction. Tests for olefin polymerization were performed in order to determine the catalytic activity of the Co(II) complexes. Chapter I presents a brief introduction to homogenous catalysis, highlighting the reactions catalyzed by the type of compounds described in this thesis, namely olefin polymerization and oligomerization and reactions catalyzed by the complexes bearing α-diimines and P,O type ligands. Chapter II is dedicated to the description of the synthesis of new α-diimines cobalt (II) complexes, of general formula [CoX2(α-diimine)], where X = Cl or I and the α-diimines are bis(aryl)acenaphthenequinonediimine) (Ar-BIAN) and 1,4-diaryl-2,3-dimethyl-1,4-diaza-1,3-butadiene (Ar-DAB). Structures solved by single crystal X-ray diffraction were obtained for all the described complexes. For some of the compounds, X-band EPR measurements were performed on polycrystalline samples, showing a high-spin Co(II) (S = 3/2) ion, in a distorted axial environment. EPR single crystal experiments on two of the compounds allowed us to determine the g tensor orientation in the molecular structure. In Chapter III we continue with the synthesis and characterization of more cobalt (II)complexes bearing α-diimines of general formula [CoX2(α-diimine)], with X = Cl or I and α-diimines are bis(aryl)acenaphthenequinonediimine) (Ar-BIAN) and 1,4-diaryl-2,3-dimethyl- 1,4-diaza-1,3-butadiene (Ar-DAB). The structures of three of the new compounds synthesized were determined by single crystal X-ray diffraction. A NMR paramagnetic characterization of all the compounds described is presented. Ethylene polymerization tests were done to determine the catalytic activity of several of the Co(II) complexes described in Chapter II and III and their results are shown. In Chapter IV a new rigid bidentate ligand, bis(1-naphthylimino)acenaphthene, and its complexes with Zn(II) and Pd(II), were synthesized. Both the ligand and its complexes show syn and anti isomers. Structures of the ligand and the anti isomer of the Pd(II) complex were solved by single crystal X-ray diffraction. All the compounds were characterized by elemental analysis, MALDI-TOF-MS spectrometry, and by IR, UV-vis, 1H, 13C, 1H-1H COSY, 1H-13C HSQC, 1H-13C HSQC-TOCSY and 1H-1H NOESY NMR when necessary. DFT studies showed that both conformers of [PdCl2(BIAN)] are isoenergetics and can be obtain experimentally. However, we can predict that the isomerization process is not available in square-planar complex, but is possible for the free ligand. The molecular geometry is very similar in both isomers, and only different orientations for naphthyl groups can be expected. Chapter V describes the synthesis of new P, O type ligands, β-keto phosphine, R2PCH2C(O)Ph, and acetamide phosphine R2PNHC(O)Me, as well as a series of new cobalt(III) complexes namely [(η5-C5H5)CoI2{Ph2PCH2C(O)Ph}], and [(η5- C5H5)CoI2{Ph2PNHC(O)Me}]. Treating these Co(III) compounds with an excess of Et3N, resulted in complexes η2-phosphinoenolate [(η5-C5H5)CoI{Ph2PCH…C(…O)Ph}] and η2- acetamide phosphine [(η5-C5H5)CoI{Ph2PN…C(…O)Me}]. Nickel (II) complexes were also obtained: cis-[Ni(Ph2PN…C(…O)Me)2] and cis-[Ni((i-Pr)2PN…C(…O)Me)2]. Their geometry and isomerism were discussed. Seven structures of the compounds described in this chapter were determined by single crystal X-ray diffraction. The general conclusions of this work can be found in Chapter VI.

Determinação do teor de compostos aromáticos policíclicos de óleos minerais isolantes para transformadores

Mestrado em Engenharia Química - Ramo Optimização Energética na Indústria Química

Hidrocarbonetos policíclicos aromáticos (HPAS) em cachaça, rum, uísque e álcool combustível

The concentration of 15 polycyclic aromatic hydrocarbons (PAHs) in 57 samples of distillates (cachaça, rum, whiskey, and alcohol fuel) has been determined by HPLC-Fluorescence detection. The quantitative analytical profile of PAHs treated by Partial Least Square - Discriminant Analysis (PLS-DA) provided a good classification of the studied spirits based on their PAHs content. Additionally, the classification of the sugar cane derivatives according to the harvest practice was obtained treating the analytical data by Linear Discriminant Analysis (LDA), using naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benz[a]anthracene, benz[b]fluoranthene, and benz[g,h,i]perylene, as a chemical descriptors.

Estudo da influência de compostos recalcitrantes na remoção de matéria orgânica biodegradável no tratamento de efluente de refinarias de petróleo

Petroleum Refinery wastewaters (PRW) have hart-to-degrade compounds, such as: phenols, ammonia, cyanides, sulfides, oils and greases and the mono and polynuclear aromatic hydrocarbons: benzene, toluene and xylene (BTX), acenaphthene, nitrobenzene and naphtalene. It is known that the microrganisms activity can be reduced in the presence of certain substances, adversely affecting the biological process of wastewater treatment. This research was instigated due the small number of studies regarding to this specific topic in the avaiable literature. This body of work ims to evaluate the effect of toxic substances on the biodegradability of the organic material found in PRW. Glucose was chosen as the model substrate due to its biodegradable nature. This study was divided into three parts: i) a survey of recalcitants compounds and the removal of phenol by using both biological and photochemical-biological processes; ii) biomass aclimation and iii) evaluation of the inhibitory effect certain compounds have on glucose biodegradation. The phenol degradation experiments were carried out in an activity sludge system and in a photochemical reactor. The results showed the photochemical-biological process to be more effective on phenol degradation, suggesting the superioruty of a combined photochemical-biological treatment when compared with a simple biological process for phenol removal from industry wastewaters. For the acclimation step, was used an activated sludge from industrial wastewaters. A rapid biomass aclimation to a synthetic solution composed of the main inhibitory compouns fpund in a PRW was obtained using the following operation condition: (pH = 7,0; DO ≥ 2,0 mg/L; RS = 20 days e qH = 31,2 and 20,4 hours), The last part was consisted of using respirometry evaluation toxicity effects of selected compounds over oxygen uptake rate to adaptated and non adaptated biomass in the presence of inhibitory compounds. The adaptated sludge showed greater degration capacity, with lower sensibility to toxic effects. The respirometry has proved to be very practical, as the techiniques used were simple and rapid, such as: Chemical Oxygen Demand (COD), Dissolved Oxygen (DO), and Volatile Suspended Solids (VSS). Using the latter it is possible to perform sludge selection to beggingthe process; thus allowing its use for aerobic treatment system`s behacior prediction

Tratamento eletroquímico de água produzida sintética para remoção de hidrocarbonetos policíclicos aromáticos

The aim of this work is the treatment of produced water from oil by using electrochemical technology. Produced water is a major waste generated during the process of exploration and production in the oil industry. Several approaches are being studied aiming at the treatment of this effluent; among them can be cited the biological process and chemical treatments such as advanced oxidation process and electrochemical treatments (electrooxidation, electroflotation, electrocoagulation, electrocoagulation). This work studies the application of electrochemical technology in the treatment of the synthetic produced water effluent through the action of the electron, in order to remove or transform the toxic and harmful substances from the environment by redox reactions in less toxic substances. For this reason, we used a synthetic wastewater, containing a mixture H2SO4 0,5M and 16 HPAs, which are: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene, benzo (a) anthracene, chrysene, benzo(b)fluoranthene, benzo(k) fluoranthene, benzo(a)pyrene, indeno(1,2,3-cd)pyrene, dibenzo(a, h)anthracene, benzo(g, h, i)perylene. Bulk electrochemical oxidation experiments were performed using a batch electrochemical reactor containing a pair of parallel electrodes, coupled with a power supply using a magnetic stirrer for favoring the transfer mass control. As anodic material was used, a Dimensionally Stable Anode (DSA) of Ti/Pt, while as cathode was used a Ti electrode. Several samples were collected at specific times and after that, the analysis of these samples were carried out by using Gas Chromatography Coupled to Mass Spectrometry (GC - MS) in order to determine the percentage of removal. The results showed that it was possible to achieve the removal of HPAs about 80% (in some cases, more than 80%). In addition, as an indicator of the economic feasibility of electrochemical treatment the energy consumption was analyzed for each hour of electrolysis, and based on the value kWh charged by ANEEL, the costs were estimated. Thus, the treatment costs of this research were quite attractive

Optimization of photo-polymerized sol gel monolithic stationary phases prepared in polyacrylate-coated fused-silica capillaries for capillary electrochromatography

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Geochemistry of pockmark sediments from the inner Oslofjord

Pockmarks are geological features that are found on the bottom of lakes and oceans all over the globe. Some are active, seeping oil or methane, while others are inactive. Active pockmarks are well studied since they harbor specialized microbial communities that proliferate on the seeping compounds. Such communities are not found in inactive pockmarks. Interestingly, inactive pockmarks are known to have different macrofaunal communities compared to the surrounding sediments. It is undetermined what the microbial composition of inactive pockmarks is and if it shows a similar pattern as the macrofauna. The Norwegian Oslo Fjord contains many inactive pockmarks and they are well suited to study the influence of these geological features on the microbial community in the sediment. Here we present a detailed analysis of the microbial communities found in three inactive pockmarks and two control samples at two core depth intervals. The communities were analyzed using high-throughput amplicon sequencing of the 16S rRNA V3 region. Microbial communities of surface pockmark sediments were indistinguishable from communities found in the surrounding seabed. In contrast, pockmark communities at 40 cm sediment depth had a significantly different community structure from normal sediments at the same depth. Statistical analysis of chemical variables indicated significant differences in the concentrations of total carbon and non-particulate organic carbon between 40 cm pockmark and reference sample sediments. We discuss these results in comparison with the taxonomic classification of the OTUs identified in our samples. Our results indicate that microbial surface sediment communities are affect by the water column, while the 40 cm communities are affect by local conditions within the sediment.

Alkane and hydrocarbon concentrations of ODP Leg 104 sites

Sedimentary extractable organic matter was analyzed at three ODP Leg 104 sites in the Norwegian Sea. Organic carbon content ranged from less than 0.1% to a maximum of 1.8%. Extractable organic matter content and unresolved complex mixture concentrations were low and randomly distributed. Low levels of aliphatic (branched and normal) and aromatic hydrocarbons were detected in all of the sediments analyzed. Total aliphatic and aromatic hydrocarbon concentrations ranged from 176 to 3,214 and 6 to 820 ppb, respectively. The concentrations of individual aliphatic (n-C15 to n-C32) and aromatic (two- to five-ring) hydrocarbons were generally less than 50 ppb and less than 10 ppb, respectively. No significant trend with sub-bottom depth was observed in either bulk organic matter or individual hydrocarbon concentrations. The predominant source of Cenozoic sedimentary hydrocarbons is concluded to be ice-rafted debris from the adjacent continent. All sites contain a mixture of recycled, mature petroleum-related and terrestrially derived hydrocarbons.